The purpose of the proposed research is to investigate the effects of rearing kittens with artificially induced strabismus upon the development of receptive field properties of visual neurons. We have shown that rearing kittens with unilateral esotropia results in wholesale changes of various response properties among striate neurons innervated (or dominated) by the deviating eye, and that to our surprise, similar effects were also found among the cells dominated by the non-deviating eye. We intend to confirm these results and extend our investigations to 1) resolve significant discrepancies which exist between our results and findings from other laboratories with respect to cortical effects of strabismus rearing, and 2) to elucidate developmental mechanisms underlying the anomalies observed in the non-deviating eye. For this, various rearing procedures will be applied in order to create necessary visual conditions during the critical developmental period. Upon completion of the rearing procedures, extracellular single cell recordings will be made in the LGN, the striate cortex, and area 18. Special emphasis will be placed upon the comparisons between esotropic cats and normally reared animals, and between the effects in the deviating eye and those in the non-deviating eye of our experimental animals. The proposed experiments will contribute to a better understanding concerning the developmental mechanisms underlying the major anomalies associated with strabismus, anisometropia, and amblyopia.